Isoleer in plaats van de verwarming hoger te zetten.

In this sentence, isoleer means insulate, not isolate in the usual English sense.

• isoleren = to insulate / to isolate
• In home and energy contexts, it usually means to insulate
• So Isoleer! means Insulate!

Dutch often uses the same verb where English would choose a more specific word based on context.

Isoleer is the imperative form, used for giving advice, instructions, or commands.

So:

• Isoleer. = Insulate.
• Ik isoleer. = I insulate / I am insulating.
• Isoleert is a present-tense form used with u or hij/zij/het, not for a direct command to jij in this style.

This sentence is giving advice directly to the reader: Insulate instead of turning up the heating.

In plaats van means instead of.

Examples:

• Thee in plaats van koffie = Tea instead of coffee
• Fietsen in plaats van rijden = Cycling instead of driving

In your sentence:

• Isoleer in plaats van ... = Insulate instead of ...

It introduces the alternative action that someone should do less of or avoid.

After in plaats van, Dutch often uses an infinitive construction with te when the following idea is a verb phrase.

So:

• in plaats van te wachten = instead of waiting
• in plaats van geld uit te geven = instead of spending money
• in plaats van de verwarming hoger te zetten = instead of turning up the heating

Here, te zetten is the infinitive part of the verb phrase.

A helpful pattern is:

• in plaats van + noun
• in plaats van + te + infinitive

In this sentence, the infinitive phrase includes an object and an adverb:

• de verwarming = the heating
• hoger = higher
• te zetten = to set / to turn up

Both can work, but de verwarming hoger zetten is a very common, natural Dutch way to say turn up the heating.

• hoger zetten = set higher / turn up
• verhogen = increase / raise

So these are similar:

• de verwarming hoger zetten
• de verwarming verhogen

But hoger zetten sounds especially idiomatic in everyday speech when talking about heating, volume, settings, etc.

Compare:

• Zet de muziek harder. = Turn the music up.
• Zet de thermostaat hoger. = Turn the thermostat up.

De verwarming usually means the heating or the heating system.

Depending on context, it can refer to:

• the general heating in a house
• the central heating
• sometimes a radiator, though that is more specifically de radiator

In this sentence, de verwarming hoger zetten means turn up the heating, not physically moving a heater upward.

Because verwarming is a de-word in Dutch:

• de verwarming

Unfortunately, grammatical gender in Dutch often has to be memorized word by word. There is not always a reliable rule from the English meaning alone.

A useful thing to learn is the noun together with its article:

• de verwarming
• het huis
• de muur

Dutch uses hoger because the idea is literally set the heating higher.

So:

• hoog = high
• hoger = higher

This matches the idea of increasing a setting, like:

• de temperatuur hoger zetten = set the temperature higher
• het volume hoger zetten = turn the volume up

English often says turn up the heating, which sounds less literal. Dutch commonly expresses that with hoger zetten.

Because the sentence ends with an infinitive phrase, and in Dutch, verbs in such phrases often come at the end.

The phrase is:

• de verwarming hoger te zetten

The infinitive verb zetten goes to the end of that group.

Dutch word order often places verbs later than English does, especially in subordinate structures and infinitive constructions.

Compare:

• Ik probeer de deur te openen. = I try to open the door.
• Hij besloot naar huis te gaan. = He decided to go home.
• in plaats van de verwarming hoger te zetten = instead of turning up the heating

Yes, the object is not stated explicitly, but Dutch allows that when the meaning is obvious from context.

So Isoleer here means something like:

• Insulate your home
• Improve insulation
• Add insulation

This is common in slogans, advice, and short informational texts. The exact object is understood from the situation.

Yes, a comma is possible, especially if you want a slight pause, but it is often written without one.

Both can appear depending on style:

• Isoleer in plaats van de verwarming hoger te zetten.
• Isoleer, in plaats van de verwarming hoger te zetten.

Without the comma, it feels more streamlined and is very common in advice slogans or short practical statements.

The structure is:

• Isoleer = imperative main verb
• in plaats van = instead of
• de verwarming hoger te zetten = infinitive phrase

So literally:

• Insulate instead of the heating higher to set

But natural English is:

• Insulate instead of turning up the heating.

This is a good example of Dutch using:

1. an imperative at the start
2. a fixed expression (in plaats van)
3. an infinitive phrase with te at the end